1. Field of the Invention
An electrical distribution system includes a plurality of separate consumer modules for supplying power to a plurality of consumer loads, respectively. Each of the consumer modules includes an overload fault detection device for automatically interrupting the supply of power to a given consumer load upon the detection of a fault therein by an overload protection arrangement. When the voltage drop across a measuring resistor exceeds a given threshold value, a non-conducting transistor becomes conductive, thereby opening a gate circuit to disconnect the consumer load from its power supply. To customize the consumer modules, resistors of varying resistance values may be selected manually or by remote control to correspond with the power demand requirements of the associated consumer load.
2. Description of the Related Art
In a modular electrical power distribution bus system commonly used in automation technology, several consumers are usually connected together via a connection device to define a specific subdistribution segment which is connected by a segment coupler to the main power supply bus which in turn is connected with and controlled by a control station having a master control panel. The bus system can be formed of conductor line or wireless connections, where, in the latter case, supply voltages are delivered to the connecting devices not from the segment coupler but, for instance, from another supply source, wherein control of connecting devices I effected by wireless means, for example, via radio.
In the segment coupling device there is normally provided a first current limiter device for the entire segment. If a defect occurs in the segment, for example, a short circuit, then the entire segment is separated from the bus by the segment coupling device, whereby the supply of power to the consumers of that segment is limited.
In this way, the entire segment is out of action, therefore, it is also known that one can associate an additional separate current limiter device in each case for the individual connecting devices. It has be discovered that a major disadvantage to this prior arrangement is that upon the response of this device to a fault condition, the other consumers of the segment are also disconnected, and it is not possible then quickly and simply identify the faulty consumer among the large number of consumers.
The German patent No. DE 100 47 114 C1 describes a protective circuit for voltage limitation for a device that is to be protected in a separable manner by means of a circuit element. That is done by a microdevice in the form of an electronic switch or, under certain circumstances, by a relay with a control circuit having a voltage sensor control device. The switch separates the element that is to be protected galvanically. As another example, the International Publication No. WO 00/62394 describes a safety barrier for the purpose of limiting the current and the voltage. Current limitations can be adjusted manually at the location of the particular connecting device.
The present invention was developed to provide an improved fault protection system in which the recognition and processing of failure situations will be greatly simplified.